Daniel works on cultural and intellectual history, U.S. foreign relations, U.S.-Europe relations, Jewish studies, and the history of the human sciences. He is completing a book manuscript, provisionally entitled Democracy in Exile: Hans Speier and the Rise of the Defense Intellectual, which is under contract with the United States in the World series at Cornell University Press. The book examines the impact of German exiles from National Socialism on the culture, institutions, and foreign policies of the postwar United States.